Apparatus for forming fin particles

ABSTRACT

To alter feedstock material, the material is exposed to laser radiation applied at a selected angle of incidence, intensity and wavelength related to the refractive index of the feedstock material. Fine uniform particles may be formed through vapor explosion and/or plasma formation and used by this method to coat surfaces, such as with paint or adhesive or to supply uniform small particles to a heat engine. Moreover, moving materials such as a column of liquid may be subjected to high internal pressure and temperature for creating physical and chemical changes.

This application is a division of application Ser. No. 07/492,928, filedMar. 13, 1990 now U.S. Pat. No. 5,044,565.

BACKGROUND OF THE INVENTION

This invention relates to apparatuses and techniques for forming andusing fine particles.

It is known to fragment materials into small particles by vaporexplosion. In vapor explosion, energy is applied to the interior of thematerial causing it to rapidly expand and form ultrafine particles in anexplosion-like effect.

Early publications discussing vapor explosion are "Dynamics andEnergetics of the Explosive Vaporization of Fog Droplets by a 10.6-UMLaser Pulse", by Peter Kafalas and Jan Harrman, APPLIED OPTICS, v. 12,n. 4, April 1973, pp. 772-775 and "Fog Droplet Vaporization andFragmentation by a 10.6-UM Laser Pulse", by Peter Kafalas and A. P.Ferdinand, Jr., APPLIED OPTICS, v. 12, n. 1, Jan. 1983, pp. 29-33.Moreover, U.S. Pat. No. 4,620,098 describes the formation of ultrafineparticles of several useful compounds using lasers and gas dispersion.

There are several known practical uses of apparatuses and processes thatgenerate particles. One such use is in spray painting and another is fornebulizers in medicine. In prior art spray painting equipment, theparticles are formed by high velocity gases or vibrators. The use ofhigh velocity gas flows has the disadvantage of wasting substantialamounts of paint as a result of the aerodynamic flow around objects andthe use of vibrators, such as piezoelectric crystals, has a disadvantagein that the piezoelectric crystals which have commonly been used withthe high velocity gas flows create particles larger than desirable forsome applications.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a novel methodand apparatus for preparing and controlling fine particles in accordancewith their use.

It is a further object of the invention to provide a novel method andapparatus for forming particles by vapor explosion and/or plasmaformation and controlling the particles in accordance with a specificuse of the particles.

It is a still further object of the invention to provide a novel methodand apparatus for laser vapor explosion and/or plasma formation ofmaterials to form fine particles and the use of fine particles resultingtherefrom at low velocities.

It is a still further object of the invention to provide a noveltechnique for coating surfaces.

It is a still further purpose of the invention to provide a noveltechnique for forming and using sprays.

It is a still further object of the invention to provide a noveltechnique for forming and using irregularly shaped particles.

It is a still further object of the invention to provide a noveltechnique for causing physical and chemical processes to occur underhigh temperature and pressure in a continuous process.

It is a still further object of the invention to provide a noveltechnique for combustion.

In accordance with the above and further objects of the invention, afeedstock material is selected and converted to very fine particles byvapor explosion and/or plasma formation. The particles are collected tothe appropriate density and are applied to the place they are to be usedin a low velocity controlled flow.

To cause vapor explosion and/or plasma formation, energy is introducedinto the feedstock material by a laser beam. The particles are formed tobe no more than 1 millimeter in diameter by controlling the energy, andafter the particles are formed, they are moved by the flow control meansat a velocity no greater than 5 meters per second. Generally, thepressures will be lower than 1 atmosphere above atmospheric pressure.For most applications, the particles will be less than 500 microns indiameter and the velocities lower than 1/10 to 1/2 meter per second. Thedescribed velocity is partly determined by the diameter of the exit portand should generally be low enough to avoid turbulance.

Preferably, one or more feeders supply the feedstock to one or morefocused lasers which create the vapor explosion. In some applications,such as the coating of objects, vapor explosion and/or plasma formationwill be within or near a mass controller. The mass controller in theseapplications confines the ultrafine particles and may, accumulateparticles from more than one source as appropriate. A flow controllermoves the particles from the mass controller to the place where they areto be utilized such as by applying them to a surface as paint. In otherapplications, such as combustion, the fine particles may remainsubstantially in one place and are acted upon such as by mixing with airand burning.

The feeder may be a container having a outlet port, preferably with avalve that controls the flow rate. The flow may be by gravity orpressure through an adjustable opening communicating with the area forvapor explosion. In the area for vapor explosion and/or plasmaformation, the atomizer for causing vapor explosion and/or plasmaformation advantageously transmits laser light at the proper frequencyand irradiance in accordance with the refractive index and the amountand velocity of feedstock material to cause vapor explosion and/orplasma formation.

To supply the laser light, the atomizing means for vapor explosionand/or plasma formation may include a plurality of lasers or one laser.Preferably, the laser light is collected and transmitted to the properlocation by a light pipe or beam or other light conductor. Theirradiance may be measured for easier control. For many applications,the frequency and the power applied to the laser are controllable in amanner known in the art.

To use the particles such as in painting, the flow rate of particles isselected in relation to the thickness of the coat and the area velocityof the nozzle with respect to the surface. The feedstock feed rate isrelated to: (1) the rate of application of the particles; (2) the lossof particles; and (3) the conversion to and loss of vapor. The number offeeders and the flow rate from each feeder are taken into account todetermine the feed rate into the particle control means. The particlecontrol means may be a tube and its size and outlet port are areadjusted for the number and flow rate of the individual feeders.

The irradiance of the lasers are set and energized so that light isapplied by beam conductors to the area of vapor explosion and/or plasmaformation, causing particles to flow into the tube. The tube is pointedat the location of application of the particles and gas from a tankserving as a flow control means is turned on to provide:, (1) gas flowat a pressure sufficiently low to avoid back pressure moving theparticles back into the explosion area; and (2) gas flow at a flow ratesufficiently low to avoid venturi effects that might pull liquid fromthe feeders too rapidly.

The selection of frequency and irradiance of the light from the laser inaccordance with the refractive index of the material and its rate offlow control the size of the particles developed. The particle size maybe caused to be uniform and of a predetermined size by causing vaporexplosion and/or plasma formation to occur at a selected energy levelthat is uniform in the exploding feedstock. The uniformity of energylevel controls the spatial heating and may occur over a large area at auniform energy level or only at an energy node with the energy nodebeing controlled to be at the irradiance level needed.

The location of energy nodes is determined by frequency, angle ofincidence, and irradiance of the radiation or irradiance and the sizeand refractive index of the material irradiated and spatial mode andpolarization of the illuminating beam. For example, a gaussian beam atan acute angle of incidence to a radius of a particle (off axis)energizes the outside or off axis area of a particle, whereas planewaves at any angle and gaussian waves on axis (radial to particle) focusenergy at one or more small continguous volumes or nodes within theparticle.

Instead of causing vapor explosion and/or plasma formation, thefeedstock material may be caused to undergo chemical reactions orphysical changes in a continuous process. To cause such reactions orphysical changes, the feedstock is moved in a continuous column orstream or aerosol stream and impacted with light from the laser orlasers to create pressure and temperature: (1) below the vapor explosionand/or plasma formation level but high enough, such as severalatmospheres of pressure, to cause the chemical reaction or physicalreaction; or (2) to cause vapor explosion or plasma formation and photoassisted combustion. This pressure and temperature may be used to makechemical and physical changes in the feedstock material or burning in acontinuous process.

From the above description, it can be understood that the method andapparatus of this invention has several advantages, such as: (1)extremely small particles may be formed without the particles having ahigh velocity or pressure; (2) the particles may be easily controlled tobe useful without excessive waste or undesirable conversion to aerosolat low irradiance, such as for painting or for the general formation ofaerosols such as in medical applications or spraying insecticides or thelike; (3) there is reduced waste of the feedstock material because ofthe low velocity and small amount of vapor formed; (4) contamination andair pollution are reduced; (5) instead of forming particles, thepressure and temperature may be controlled to cause continuous on linephysical and/or chemical reactions; (6) high temperature combustioncapable of reducing a wide range of waste products to a more desirableform; and (7) providing more complete combustion of fuel photo throughenhanced combustion.

SUMMARY OF THE DRAWINGS

The above noted and other features of the invention will ,be betterunderstood from the following detailed description, when considered withreference to the accompanying drawings in which:

FIG. 1 is a block diagram of a process for forming and using smallparticles in accordance with the invention;

FIG. 2 is a block diagram of an apparatus for forming and usingparticles in accordance with the invention;

FIG. 3 is a partly schematic, partly sectioned, fragmentary view of aportion of the apparatus for forming and using particles in accordancewith an embodiment of the invention;

FIG. 4 is a partly schematic, partly sectioned, fragmentary view ofanother embodiment of the portion of the apparatus for forming and usingparticles similar to that of FIG. 3 but is intended to use a solid as afeedstock rather than a liquid;

FIG. 5 is a simplified perspective view of another of the apparatus forforming and using particles of FIG. 3 or FIG. 4;

FIG. 6 a simplified sectional view of a portion of the embodiment ofFIG. 2 including a mass controller and a flow controller which areanother embodiment of the invention;

FIG. 7 is a simplified sectional view of a portion of another embodimentof the mass controller and the flow controller in accordance with theinvention;

FIG. 8 is a simplified sectional view of still another embodiment of themass controller and the flow controller in accordance with an embodimentof the invention;

FIG. 9 is another embodiment of the invention utilizing partssubstantially the same as the prior embodiments bu providing an entirelydifferent effect; and

FIG. 10 another embodiment of the invention as used for combustion.

DETAILED DESCRIPTION

In FIG. 1, there is shown a block diagram of a process 10 for formingand using small particles including the step 12 of selection offeedstock material, the step 14 of laser illumination, the step 15 ofparticle, vapor and/or plasma formation, the step 16 of particledispersion, concentration and flow control preparation and the step 18of deposition, injection, inhalation, spraying and/or incineration. Inthis process, liquids such as paints or medical liquids which are to bebroken into fine particles for application are illuminated withelectromagnetic energy to cause them to break into very fine particles.In some embodiments, after the selected feedstock is reduced to smallparticles, the small particles are gathered together or dispersed to theproper concentration and then are caused to move to the location whereparticles are to be utilized as indicated by step 16.

The step 14 of laser illumination and the step 15 of vapor and/or plasmaand/or particle formation utilize the energy from a laser. In thepreferred embodiment, light from a laser is transmitted into thematerial at the appropriate frequency and irradiance for that explosionand/or plasma formation, thus resulting in a low velocity cloud or mistof fine particles. The particle dispersion, concentration and flowcontrol preparation 16 may require the confinement of these particles,which confinement is possible because of the low velocity. Theconfinement need only be to the appropriate density at which they are tobe moved at low velocity to the place of utilization as indicated by theflow control step 16.

In this specification, electromagnetic size transformation meansparticle formation, vapor explosion and/or plasma formation. In thisspecification, particle formation, vapor explosion and/or plasmaformation means separating contiguous portions of feedstock material inthe solid phase or liquid phase into vapor or particles or both, eithercharged as in a plasma or not charged. The particle formation meansforms small particles without converting more than 20 percent of thematerial into the vapor phase. Small particles are particles having adiameter in the case of a sphere, or a largest dimension in the case ofirregularly shaped particles, no greater than 1/2 of a millimeter (500microns). If vapor is desired, this can be accomplished by increasingthe power of the laser. The contiguous portions of feedstock materialare separated into small particles by introducing electromagnetic energyinto the feedstock material.

In this particle formation, vapor explosion and/or plasma formationprocess, the electromagnetic energy is generally introduced by a laserbeam, the characteristics of which are selected to have power sufficientfor the accumulation of the appropriate amount of energy in the materialto be separated into particles by vapor explosion and/or plasmaformation and to be at a frequency appropriate for this material.

The frequency of the applied electromagnetic energy, the refractiveindex of the material to be broken into particles and the power at whichthe electromagnetic energy is applied all affect the internal energylevel within the feedstock material and are selected to cause the vaporexplosion and/or plasma formation. This internal energy level may beexpressed either in terms of an electromagnetic field irradiance or interms of temperature. Generally, it is accepted that vapor explosionand/or plasma formation will occur at temperatures 9/10 of the criticaltemperature of the feedstock material. The heating effect from a laserbeam of given irradiance is directly related to the refractive index ofthe material.

Critical temperature in this specification has its usual meaning whichis the temperature of the liquid-vapor critical point which is also thetemperature above which feedstock material has no liquid-vaportransition. Obviously, the introduced power is related to the associatedenergy needed for the vapor explosion and/or plasma formation and to thevelocity between the laser beam introducing the power and the materialwhich is being exploded.

In FIG. 2, there is shown a block diagram of apparatus 20 for formingand using small particles having a feeder 22, an atomizer using vaporexplosion and fragmentation 24, a mass controller 26 and a flowcontroller 28. The feeder 22 supplies a material to the atomizer 24which breaks it into particles of less than 500 microns by vaporexplosion and/or plasma formation and supplies them to a mass controller26 which controls the density of the particles and the amount of mass.The flow controller 28 uses the particles in a process, such as forpainting or forming medical sprays or the like.

To supply the feedstock material, the feeder 22 contains means forcontrolling the rate at which the feedstock material is supplied. As asimple example, it may be a container for a liquid having a smallorifice at its bottom through which the liquid flows in a steady streamby gravity at a rate controlled by the size of the orifice. The liquidmay be any liquid that is to be used as fine particles such as, forexample, paint to be used in spray painting or fuel to be atomized infuel injection

The atomizer using vapor explosion and fragmentation 24 receives thefeedstock material from the feeder 22 and applies energy to it as itflows from the feeder 22, breaking the material into particles of thedesired shape. It supplies energy generally by laser at an irradianceand for a time sufficient to cause vapor explosion and/or plasmaformation. Upon formation, the particles are substantially confined forlater use.

The mass controller 26 works in conjunction with the flow controller toprovide a confined working area from which the particles may be directedto the proper source. For example, it may be a simple compartment whichis slightly pressurized to move the particles at a low mist velocity. Inthis specification, low mist velocity means that the average velocity ofall of the particles in a single direction toward their ultimatedestination is less than 1 meter per second and has a pressure exertedby the particles of less than 1/10 of an atmosphere above atmosphericpressure.

The feeder 22 may contain one or several sources of feedstock materialeither used in conjunction with each other or individually to supplyseveral streams of fluid for atomizing, using vapor explosion and/orplasma formation. The particles formed by the vapor explosion and/orplasma formation may be accumulated in either a single mass controller26 or a plurality of mass controllers. Several containers may be used toreach the proper density in the mass controller 26 for the particularapplication while maintaining the size of the material being movedwithin a range suitable for atomization by one or a plurality of laserbeams.

In FIG. 3, there is shown a partly sectioned and partly schematic viewof a feeder 22 and atomizing means 24A and 24B (24 in FIG. 2) usingvapor explosion and/or plasma formation in which the feeder 22 iscoupled to the atomizing means 24A and 24B in such a way that liquidwithin the feeder 22 flows at a controlled rate past a vapor explosionand/or plasma formation location or area to form fine particles andvapor for application to the mass controller 26 (not shown in FIG. 3)which confines the particles and vapor if vapor is to be used.

As shown in FIG. 3, the feeder 22 includes a housing 30, having a cavity32 for containing a liquid, an outlet port 34, a valve 36 forcontrolling flow through the outlet port 34 and a coupling fixture 38for coupling the atomized particles and vapor to the mass controller 26(FIG. 2). The cavity 32 may contain any liquid from which it is desiredto form particles, such as a paint which is to be used in a spraypainting operation or medical liquids to be vaporized in a nebulizer forapplication to patients or fuel to be vaporized for combustion.

The outlet port 34 permits the liquid to flow under the force of gravityor under a slight pressure in a controlled stream through an explosionarea 25 to form the particles, and the coupling fixture 38 is positionedto receive the particles while permitting them to be spread apartadequately to avoid their being combined into a liquid again. The valve36 is positioned in the outlet port 34 to adjust the flow rate and canbe any type of valve such as a needle valve or the like. The housing 30may be pressurized or unpressurized for further control of flow rate asdesired.

The atomizing means 24A and 24B for forming particles by vapor explosionand/or plasma formation include: (1) a plurality of transmission paths,three of which are partly shown at 40A, 40B and 40C; (2) one or moreenergy sources coupled to the transmission paths for application ofenergy, one of which is shown at 42C for the transmission path 40C; (3)a corresponding plurality of energy control portions , one for eachenergy source and transmission path, the energy controller 44C beingshown coupled to the energy source 42C for explanation purposes; and (4)the explosion area 25. While a plurality of transmission paths, energysources and controls are contemplated in the preferred embodiment, onlyone is necessary if it provides adequate power and instead of beingidentical, different versions may be used to provide the propercombination of power for vapor explosion and/or plasma formation.

In the embodiment of FIG. 3, the light transmission paths such as 40A,40B and 40C each include corresponding light conductors 46A, 46B and 46Cwhich are coupled at one end to the energy sources such as the oneillustrated by 42C in FIG. 3 and at the other end to corresponding lensarrangements 48A, 48B (not shown) and 48C for focusing light on thevapor explosion and/or plasma formation area.

The lens arrangements, such as 48A and 48C shown in FIG. 3, focus lightchanneled through the light conductors 46A-46C, light pipes or beampaths into the outlet port 34 at a vapor explosion and/or plasmaformation area so that the energy may impinge upon the liquid flowingtherethrough to create a fine mist of particles at low velocity whichmove through the coupling fixture 38 by gravity. With this arrangement,the liquid flowing through the cavity 32 is converted in a controlledamount to fine particles which are applied to the mass controller 26(FIG. 2) for application to a surface by the flow controller 48 (FIG.2).

To supply light to the transmission path 40C, the energy source 42Cincludes a lens-coupling assembly 50C, a laser array 52C and a meter54C. The laser array 52C supplies light to the lens-coupling assembly50C which collects an adequate amount of light for the energy requiredand applies it through the light transmission path 40C.

The collected light is measured by the meter 54C to properly adjust thepower in accordance with the desired outlet particles using the energycontrols 44C. Feedback controls may also be used between the meter 54Cand the energy controls 44C where desired to control variations in theirradiance of light to provide predictable and reliable results. Similarenergy sources are also provided for the other transmission paths.

The lens coupling assembly 50C includes a housing 60, a lens assembly 62and a photocell 64. It is mounted to receive light from the laser array52C and couple the light to the light transmission path 40C fortransmission to the outlet port 34 from the feeder 22. The photocell 64is coupled to the meter 54C by the conductor 80 to provide a signalthereto indicating the light irradiance.

The laser array 52C includes a plurality of lasers, three of which areshown at 70, 72 and 74 in FIG. 3. In the embodiment of FIG. 3, thelasers are diode lasers but may be any type of laser. The light outputis varied by the number of lasers and the controls which apply power tothe lasers. In some cases , the frequency may be tunable to accommodatedifferent liquids with different refractive indexes and in other cases,they are fixed for a fixed purpose such as a fixed source of medication,or a fuel injection system using only a specific fuel or a particularpainting operation along an assembly line so that its refractive indexis not varied.

In FIG. 4, there is shown another embodiment of feeder 22C , partlysectioned and partly schematic, similar to the feeder 22 of FIG. 3 andhaving the same parts labeled with the same reference numbers. It isshown connected to the atomizing means 24A and 24B (24 in FIG. 2) in thesame manner as the embodiment of FIG. 3. However, in the embodiment ofFIG. 4, the feeder 22C includes rollers 39A and 39B which drive a solidsuch as an aluminum wire at a controlled rate. Thus, the valve used inthe embodiment of FIG. 3 to control the flow rate of a liquid within thefeeder is unnecessary.

In the embodiment of FIG. 4, the solid is driven past the vaporexplosion and/or plasma formation location or area to form fineparticles and vapor for application to the mass controller 26 (not shownin FIG. 3) which confines the particles and vapor, if vapor is to beused , in the same manner as particles are formed from a liquid in theembodiment of FIG. 3.

In FIG. 5, there is shown a portion of an apparatus for forming andusing small particles particularly useful in coating applications, suchas painting, and having a feeder 22, a particle control means 26A, aflow control means 28A and a work piece such as 90 which is to becoated, such as by spraying. The work piece 90 may be adapted to bemoved with respect to the apparatus for forming and using smallparticles such as on an assembly line in which the work piece 90 is oneof a series of items, each of which are to be painted with the samecolor.

The feeder 22 shown in FIG. 5 includes a plurality of feeder units 22Aand 22B each of which may share an energy source or may have itsindividual energy sources. One or any number of feeder units may beutilized, and in the embodiment of FIG. 5, two are utilized. The numberof feeder units is selected to provide an appropriate density ofparticles in the particle control means 26A consistent with the requiredflow of particles for function of the apparatus and with the appropriatecoordination of the laser energy and the stream of feedstock materialthat is being converted to particles.

In the embodiment of FIG. 5, the feeder units 22A and 22B are connectedat spaced apart locations in a line along the particle control means 26Aso that they feed particles in a series in line with pressurized gassupplied by the flow control means 28A. In this manner, the total flowrate of the particles to the surface to be painted or to receive anaerosol may be adjusted to a level greater than the maximum obtainablefrom one feeder.

The feeder units 22A and 22B are identical and only feeder unit 22A willbe described herein. It includes a feeder housing 30A, a plurality oflight conductors 40A-40C being shown in FIG. 5, a source of fluid (notshown in FIG. 5) for applying new fluid through a hose 92A, a source ofpressure hose 94A and a control knob 36A for a valve to control the flowof particles formed in an explosion area (25 in FIG. 3) through acoupling unit 38A into the particle control means 26A.

The individual control valves 36A and 36B are generally adjusted toidentical feed rates which together provide a sufficient number ofparticles from the particle control means 26A. The source of pressurethrough the hose 92A can also be adjusted to control the flow rate andnew fluid may be applied through the source of pressure hose 94A toreplace fluid that is being converted to particles and leaving thefeeder housing 30A. For some applications, it is unnecessary to apply apressure through the hose 92A and fresh fluid through the source ofpressure hose 94A.

The number of feeders, the amount of particles to be produced by eachfeeder and the specific design of the feeders are all matters which areadjusted in accordance with the particular use of the apparatus.However, because the feeders are themselves adjustable and more than onefeeder can be used, control of the rate of flow of particles from theparticle control means 26A may be varied by the flow control means 28Aover a wide range without exceeding the capacity of a single feeder.

The particle control means 26A in the embodiment of FIG. 5 is a tubularcylinder 100 having a recess 102 in its bottom wall with the lowestportion of said recess being stopped by a drain valve 104. Openings inthe top of the tubular cylinder 100 provide a connection with thecoupling units 38A and 38B to the feeder housings 30A and 30B to permitparticles to flow into the particle control means 26A from the top.Cooling may alternatively be provided to the tubular cylinder 100 tocool and remove vapor through the drain valve 104. The drain valve 104further serves to remove any excess flow of particles not broken into afine mist. The flow control means 28A is connected to the tubularcylinder 100 at one end 106 and the outlet port 108 of the particlecontrol means 26A may be aimed at the surface to be coated to moveparticles onto it.

The flow controller 28 (FIG. 2) in one embodiment 28A includes apressurized tank of air communicating with the tubular cylinder 100 atthe inlet 106 through a valved conduit 112, the flow and pressure fromwhich is controlled by the valve 114. With this arrangement, a lowvelocity of air or other gas moves the particles against the surface towhich they are applied. Since the particles have substantially novelocity within the particle control means 26A which confines them, verylow velocity and low pressure air is adequate to move the particles,thus avoiding the escape of excessive vapor and an excessive number ofparticles.

In another embodiment used either with or separately from the embodiment28A, the flow controller 26 includes a source of electric potentialconnected to the surface to be coated to draw charged particles towardthe surface. The particles are charged by the vapor explosion and/orplasma formation, but in some applications a means for charging theparticles other than the laser apparatus may be used.

Before using the apparatus for forming and using small particles,certain parameters must be determined, such as for example the mass flowrate of particles to accomplish each purpose, such as coating a surface.Under some circumstances, trial runs may be necessary.

The irradiance of energy applied to the stream of feedstock must also beknown. In some cases, it can be calculated from a knowledge of therefractive index of the material and the flow rate. In other cases, itmust be determined by a trial run and adjustment to obtain the properkind of particles.

The flow of pressurized air serving as a flow controller must also beeither known or determined by adjustment to the valve 114. The pressureand flow rate must be adjusted so back pressure does not prevent theparticles from leaving the adapter where they are formed and insteadpermits them to freely enter the particle control means 26A. Moreover,the flow rate must be sufficiently low so that venturi effects do notpull liquid downwardly before it can be vapor exploded.

In operation, after the adjustments are made, the mass controller 26 ispositioned, the lasers are energized, the feeder flow is adjusted andthe feedstock material is applied in the proper manner such as forpainting.

To adjust the lasers so as to provide the proper amount of particles atan appropriate rate, the operator selects the number of lasers in alaser array such as 50C , the type of lasers, the irradiance of theirlight, the frequency of the output if the lasers are tunable and theoutput of the power sources.

The power is adjusted with the power control means controlling thevoltage to the lasers and the lasers are positioned so that light flowsthrough the light pipes or beam paths into the area for vapor explosionand/or plasma formation. The flow rate is adjusted by the valves 36A and36B and the number of feeders so that it flows into the tube 100 and thevalve 114 is adjusted to the proper flow rate.

After the equipment is adjusted, the lasers are turned on so thatparticles are formed in the feeder by vapor explosion and/or plasmaformation of liquid flowing downwardly, forming fine particles of thecoating material. The flow through valve conduit 112 gently moves theparticles at a velocity less than 1 meter per second against the workpiece 90 to coat it.

During the coating, the outlet port 108 is positioned immediatelyadjacent to the work piece 90 pointing toward the location fordeposition of the particles. If necessary, the drain valve 104 is openedand in some embodiments, the tubular cylinder 100 may be water cooled,with liquid being collected from the drain valve 104 for recirculationor disposal to avoid pollution.

Although in the preferred embodiment, the particles are moved by gaspressure to the surface for coating or to any other location in whichthey are to be utilized, other conventional means of moving particlesmay be utilized. The particles are generally charged and may beelectrostatically drawn to a surface. Moreover, additional charge may beapplied to them.

In forming the particles, uniformity of size of the particles isobtained by causing the vapor explosion and/or plasma formation to occurat the same energy level to have the same turbulent irradiance at thetime of breaking. This is done by creating a uniform field at certainpoints in a droplet which produce vapor explosion and/or plasmaformation or 9/10 of the critical temperature or as a substitute forthis, selecting the angle of incidence to a column or droplet or solidand frequency and irradiance which will create a node of high energy forthe vapor explosion and/or plasma formation. That node may occur atdifferent locations but the vapor explosion and/or plasma formationcreating the particles should create a turbulent irradiance withoutvariations of more than 10 percent for uniformity. However, the higherthis irradiance at the time of the vapor explosion and/or plasmaformation, the smaller the particles so that some control is exercisedover the size of the particles.

In FIG . 6, there is shown another flow controller 28B and masscontroller 26B, with the flow being controlled by inhaling action of aperson through a mouthpiece 120 to draw particles from an atomizer usingvapor explosion and/or plasma formation 34 of the type shown in FIG. 3through tubing 38C into the patient. This mass controller 26B and flowcontroller 28B may be used with hospital nebulizers to draw salinesolution particles and medication into the patient with efficiency.

In the embodiment shown in FIG. 6, the mass controller 26B includes ahollow housing 124, first and second exhaust tubes 126A and 126Bcommunicating through check valves with the housing 124 to permit theexpulsion of air under pres sure but not permitting air to be drawn in,a valve assembly 122 communicating with the tube 38C to permit particlesto be drawn in by vacuum pressure from the mouthpiece 120 but preventingexhaled air from the mouthpiece 120 from flowing into the tube 38C.

With this mechanism, a patient places the mouthpiece 120 in thepatient's mouth. When the patient draws inwardly, particles are drawnthrough the tube 38C which may be elongated. The force of the inhalationbends the spring 130 in the valve assembly 122 pulling a valve element132 away from a valve seat 134 to permit particles in air to enter itand flow there around into the mouthpiece 120. When the patient exhales,pressure causes the valve element 132 to fall against the valve seat 134blocking the exhaled air from the tube 38C but permitting it to flowthrough the exhaust tubes 126A and 126B.

In FIG. 7, there is shown another embodiment of mass controller 26Cwhich serves as a carburetor for receiving particles of fuel such asgasoline through a tube 38D from the atomizer 50A and 50C using vaporexplosion and/or plasma formation through conduits 46A and 46C. Acontrolled amount of particles are supplied to a heat engine shown infragmentary form at 140 for even combustion. In the carburetor 26C,particles are drawn through the tubing 38D from the mass controller intoan induction tube 144. An air filter 142 is mounted to the top of theinduction tube 144 in a conventional manner and a pivotable throttlevalve 146 is mounted to be adjusted in position and thus control thevelocity of air drawn through the air filter 142 through the inductiontube 144 into the engine 140. With this arrangement, particles are drawnby the flow of air from the tube 38D for burning in the engine 140 in amanner known in the art.

With this arrangement, uniform fine particles are drawn into the engine140 where they are quickly burned in a uniform hot flame so that thereis very little exhaust of combustible fuel. Moreover, while theparticles may be conventional gasoline, other types of particles such asfrom coal, coal slurries or the like, if sufficiently fine, may be usedin some heat engines such as 140.

In FIG. 8, there is shown a fragmentary view of a boiler having a masscontroller 26D, a flow controller 28 and a plurality of boiler tubes 150forming a portion of a boiler and a plurality of sources of radiation46A and 46C. The air paths indicated generally at 28D control thefeeding of the particles into the flame for burning. With thisarrangement, the flow of fuel into the boiler is controlled, providing ahigher degree of combustion and efficiency.

In each of these embodiments, particles are formed with a size dependentupon the turbulent irradiance. The turbulent irradiance is controlled bythe refractive index of the material, the amplitude of energy applied tothe material, the frequency of energy applied to the material, thestarting shape of the material, and the angle of incidence to thematerial at which the electromagnetic energy is applied. The particleuniformity is controlled by the vapor explosion and/or plasma formationat a uniform turbulent irradiance.

In FIG. 9, there is shown a reactor 154 having first and second sourcesof feedstock 160A and 160B, a pressure and temperature controlledreactor 162 and a collector 164. The pressure and temperature controlledreactor 162: (1) communicates with the sources of feedstock 160A and160B through valves 166A and 166B through which the flow of feedstockmay be controlled ; (2) creates pressure and temperature in the flow offeedstock in an on-line process for creating physical or chemicalchanges in one feedstock or more than one feedstock; and (3)communicates with the collector 164 which may be any suitable fractioncollector or other collector for collection of the reaction product ofthe pressure and temperature controlled reactor 162.

While in FIG. 9, two sources of feedstocks 160A and 160B are showncontrolled by valves 166A and 166B, obviously only one feedstock, suchas plastic, is necessary in some applications and multiple feedstocksources may be used. In the case of some plastics, a single polyethyleneor polyvinylchloride compound may, for example, be applied to thepressure and temperature controlled reactor 162 and through the properexertion of pressure be made linear before being collected. Similarly,multiple sources of feedstock may be reacted together in the pressureand temperature controlled reactor 162.

The pressure and temperature controlled reactor 162 is substantiallyidentical to the atomizer using vapor explosion and/or plasma formation34, two embodiments of which are shown in FIGS. 3 and 4 indicatedgenerally as 34A and 34B. However, the amplitude of the laser beams,frequencies and angle of incidence to the flow of fluid through thereaction section 34 are adjusted to be below 9/10 of the criticaltemperature at points in the column. With this adjustment, there is novapor explosion and/or plasma formation but high temperatures andpressures are exerted in the column which cause the desired reactiondepending on the selection of feedstocks. In this manner, chemicalreactions requiring high temperatures and pressures may be utilized in acontinuous process rather than in a batch process.

In FIG. 10, there is shown a vapor explosion apparatus 10A adopted tovaporize waste materials using vapor explosion and photon-aided burninghaving a source of laser energy 50F, a plurality of light conductors46A, 46B and 46C, a temperature controlled reactor 18A, a waste feed 120and a collector 164A. The waste feed 120 pumps toxic liquids through aconduit or conveys solid material such as asbestos, glass and the likeby other means such as an auger or conveyor into the temperaturecontrolled reactor 18A where it is irradiated by energy sufficient toburn it using photon aided combustion. The waste material is filteredinto collector 164A.

From the above description , it can be understood that the method andapparatus for forming and using fine particles of this invention hasseveral advantages, such as: (1) extremely small particles may be formedwithout the particles having a large velocity or pressure; (2) theparticles may be easily controlled to be useful without waste vapor orthe like for painting or for forming aerosols or spraying insecticidesor the like; (3) there is reduced waste of the feedstock materialbecause of the low velocity and small amount of vapor formed; and (4)contamination and air pollution is reduced.

Although a preferred embodiment of the invention has been described withsome particularity, many modifications and variations in the inventionare possible within the light of the above teachings. Accordingly , itis to be understood that, within the scope of the appended claims, theinvention may be practiced other than as specifically described.

What is claimed is:
 1. Apparatus for forming and using small particlescomprising:feeder means for supplying a feedstock material; atomizermeans for breaking the feedstock material into particles using vaporexplosion and/or plasma formation; said atomizer means including meansfor receiving the feedstock material from said feeder means; meanscontroller means includingg means for receiving said particles from saidatomizer means and confining said particles to a preselected densityrange; and direction control means for moving the particles within saidmass controller means to a location for use at a velocity of less than 1meter per second.
 2. Apparatus according to claim 1 in which saidatomizer means includes at least one means for applying a laser beam tosaid feedstock material.
 3. Apparatus according to claim 1 in which saidfeeder means includes at least one means for holding a liquid andsupplying the liquid to the atomizer means at a predetermined rate. 4.Apparatus according to claim 3 in which said atomizer meansincludes:laser means; means for controlling the laser means; means forcollecting light from the laser means and applying it through a lightpipe or beam path to said feedstock material; meter means for providingan indication of the intensity of energy from said laser means. 5.Apparatus according to claim 4 in which said laser means includes atleast one diode laser.
 6. Apparatus according to claim 5 in which themass controller means comprises a tube being mounted to receiveparticles from the atomizer means and to receive a flow of gas under lowpressure from the mass controller means; said tube having an open endadapted to be pointed with said open end facing in the direction of thelocation to which the particles are to be applied.
 7. Apparatusaccording to claim 1 in which said atomizer means includes a means forapplying a uniform field to the feedstock material, whereby uniformparticles are supplied.
 8. Apparatus in accordance with claim 1 in whichthe atomizer means includes a means for creating an energy node having aturbulent intensity in the material such as to create uniform particlesof a predetermined size.
 9. Apparatus in accordance with claim 1 inwhich said direction control means includes a means including air undercompression in a confined space for directing the air in a predetermineddirection.
 10. Apparatus in accordance with claim 1 in which saiddirection control means includes means for applying an electromagneticfield to direct said particles in a predetermined direction. 11.Apparatus in accordance with claim 1 in which said direction controlmeans includes means for moving a surface to be coated in juxtapositionwith said mass controller means, whereby particles are coated on saidsurface.
 12. Apparatus in accordance with claim 1 in which said feedermeans includes a means for feeding paint to said atomizer means, wherebya coat of paint is applied to a surface.
 13. Apparatus in accordancewith claim 1 in which said feeder means includes a means for feedingadhesive material to an adhesive means, whereby said direction controlmeans coats an adhesive onto a surface.
 14. Apparatus according to claim1 in which said mass controller means and direction control meansinclude means for applying said particles in juxtaposition with therespiratory tract of a patient and said feeder means includes means forfeeding a medication to said atomizer means.
 15. Apparatus according toclaim 1 in which said feeder means includes means for feeding fuel tosaid atomizer means and said mass controller means and said directioncontrol means are part of a carburetor assembly.
 16. Apparatus inaccordance with claim 1 in which said feeder means includes a means forfeeding fuel to said atomizer means and said mass controller means andsaid direction control means are part of a boiler.
 17. Apparatus forchanging the form of a feedstock comprising:feeder means for supplyingat least one feedstock material of a plurality of feedstock materials;means for irradiating said feedstock material as said feedstock materialflows continuously with electromagnetic energy having an angle ofincidence, wavelength, and intensity related to the refractive index,shape, size and velocity of movement of said feedstock material to bebelow the intensity of vapor explosion and/or plasma formation butsufficiently high to change the characteristics of at least onefeedstock material.
 18. Apparatus in accordance with claim 17 in whichsaid plurality of feedstock materials are supplied and the temperatureand pressure caused by said means for applying incident energy aresufficient to cause a predetermined chemical reaction.
 19. Apparatus inaccordance with claim 17 in which the feeder means includes means forfeeding a polymer and the pressure and intensity are sufficient to causesaid polymeric material to be linear, said pressure and temperaturebeing within a range of 2 atmospheres and 6 atmospheres and 200 degreesCentigrade to 500 degrees Centigrade, respectively.